Conventional burglar alarm systems may include ultrasonics, microwave, infra-red, bells and many other systems. The nerve centre of any alarm system is the control panel. It is where all the detection circuits terminate, and where electronics monitor the circuit for the continuous presence of a voltage. When the detection equipment is disturbed, the circuit is broken and the control panel immediately registers the loss of voltage and activates bells or sirens, warning of an intrusion.
For those conventional burglar alarm systems used in homes by families, the bells, buzzers or sirens are electronically or mechanically actuated for sounding which may reduce their alarming efficiency because the electronic or mechanical sounding will not indicate the true condition to ask for help once a robber or a thief intrudes. The universal sounding is almost the same among so many warning or alarming conditions, to thereby easily cause confusion to influence the protective measures.
The conventional burglar systems used in cars are always formed with ultrasonic or microwave units which, however, may be subject to false alarms because in certain conditions, any movement outside a protected area may trigger an alarm.
Although conventional telephone dialing equipment has been disclosed, a prerecorded alarming recorder should be separately provided to increase the installation cost of such a telephone dialing alarm.
The present inventor has found the defects of conventional burglar alarms and invented the present robbery-repelling alarm system.